A Certain Special Surprise
by Skarlashka
Summary: During one late spring season, Mikoto gets the feeling that her friends are hiding something big… and it leads to something special for many people worldwide.


**A/N:** This is a one-chapter Railgun fanfic. Thank you to Cun and GreatSnapper for beta!

* * *

 **A Certain Special Surprise**

"Where are you heading off to today, Onee-sama?"

It was early Saturday morning, a bright off-school day that promised plenty of freedom for many of Academy City's students. Within a certain room of Tokiwadai Middle School dormitories, two girls were grooming themselves to head outside.

"I was thinking of shopping at the School Garden," Mikoto replied. "I need to stock up on some stationery."

She gently pulled a brush through the locks of her fine shoulder-length hair, and gazed through the open window with a thoughtful expression. The delicate white curtains were drawn, allowing the early May sunrays to stream through and illuminate the room with their natural warmth. Her fingers mindlessly reached for her white hairclip and pinned back some stray brown locks.

"It's such good weather though; it might be a shame to spend it inside."

"You're right, Onee-sama." The younger girl finished tying the final red ribbon on her pigtails and turned to smile at Mikoto. "Once May passes, the weather will probably go downhill from there. We should enjoy spring while it lasts, no?"

Mikoto stood up from her bed, and stretched out her arms. "Ahh~ I suppose that's true. I could always pick up the stationery later. Maybe we can go out to the park and hang around there or something."

At this, her junior's eyes sparkled like giant diamonds.

"O-Onee-sama! Are you inviting me on a romantic date with you in the park?!"

Before Mikoto could even think of a retort, Kuroko had already teleported, burying her face into the electromaster's modest bosom and rubbing a cheek boldly against her chest.

"Walking among the flower beds, the sweet fragrance of spring in the air… All with my dearest Onee-sama?!"

Mikoto's eyebrows twitched, and her face heated up to turn a brilliant shade of crimson. Blue sparks flew from her bangs, a premonition for the divine punishment to come.

"You PERVERT!"

Electric tendrils burst out, knocking the teleporter back and leaving the burnt girl smoking and twitching on the ground. Mikoto huffed at the familiar sight, turning up her nose in annoyance.

"Jeez Kuroko, can you act _normal_ for once?!"

Kuroko sat up slowly, and gingerly rubbed a sore spot on her arm.

"Ah… Your love-whips are as harsh as ever, Onee-sama."

"Shut up!"

Kuroko sighed lightly, a small smile playing on her lips.

"I would gladly spend this glorious day on a date with you Onee-sama, but unfortunately, I have a lot of Judgement work to do today. I will probably have to spend the entire day at the office."

"Oh…" Mikoto frowned. "You've been pretty busy lately. Is there another big case happening?"

She tried to think back on anything Kuroko might have mentioned recently, but came up blank.

"Actually… It's more just paperwork and other things to sort out."

"Oh…" Mikoto slumped in disappointment, but then brightened up again at another thought. "Wait, Uiharu-san will be there too, right? I'll come along and hang out with you guys at the office. Let's call Saten-san as well –"

"No!" Kuroko cried suddenly. When Mikoto sent her a perplexed look, the teleporter hurriedly continued on in a clipped tone. "Judgement work is Judgement work. The office isn't a place for civilians like you to 'hang out' and chat, Onee-sama."

"Huh?! You never had any problems with us visiting before!"

"I think it's about time I put a stop to such bad habits of yours, Onee-sama," Kuroko plunged ahead in a dramatic voice. "If you continue on like this, you'll never start becoming a proper lady! As your herald and guardian, Kuroko feels obliged to step in and ensure your reputation doesn't get damaged any further! Kicking vending machines, wearing those horrible shorts under your skirt; not to mention those childish panties you bought last week–"

"Haaah?!" Mikoto's face was turning red again as she glared at her junior. "H- How do you even know about that-?!"

"– A pink rabbit hugging a winking hippo does _not_ make for a good ladies' underwear!" Kuroko continued as if she had not been interrupted. "Not to mention the atrociously matching bra! If you would just take Kuroko's example and _listen_ for once, you'd understand–"

Lightning flashed, exploding violently through the entire the room.

"STOP GOING THROUGH MY STUUUUUUFFFFF!"

XXXXXXX

"CHASERRR!"

A soda can rolled noisily out from the vending machine, a reward reaped with a vicious kick delivered by a certain angry Level 5. A hand roughly grabbed the drink, tore the ring-tab off and drained the entire thing down in just a few gulps. An aggravated fist crunched the empty aluminium into the other hand, crackling electricity bursting out between them to add to the innocent metal's demise.

"Just who does she think she is?!"

Mikoto was fuming. After the incident, the Dorm Mistress had come thundering in like a bull, telling them off and threatening a week's worth of detention. They had only managed to narrowly escape with some well-timed excuses and distractions from the other girls in the dorm who had gathered outside their room to see the commotion.

 _'Why can't Kuroko just leave me alone about such crap?! It's not like anyone's going to see my underwear or bra… What the heck?! Why am I even thinking about this?! As if I don't have enough stress to deal with already…!'_

Crushing the already-battered can into a pulp, the electromaster angrily chucked the abused metal into a nearby bin and threw herself onto a bench. She leaned back with crossed arms, and glared at the blue sky.

"Gaaahh! This sucks!"

It _was_ a nice day, but after this morning's fiasco, Mikoto really wasn't in the mood for anything much. She sat there unmoving for a long while, her mind tumbling over stray thoughts and gradually drifting into complete and utter boredom.

 _'Ahhh… Maybe Saten-san is free.'_

Digging into her skirt pocket, Mikoto pulled out her green Gekota phone. She paused briefly before typing out a short message.

 _-Hey, wanna hang out today?-_

Pressing the send button, she only had to wait a few minutes before the frog ringtone croaked out a tune.

 _-Sorry Misaka-san, but I have some schoolwork I really need to catch up on this morning. My teacher will kill me otherwise! I should be free around 12 though, so I'll let you know? Let's have lunch together!-_

Mikoto groaned, her eyebrows pulling into a small frown. Noon was still _hours_ away.

 _-Sure, text me whenever.-_

She shut the mobile closed, and sighed despite herself.

 _'Maybe I'll just stick to the original plan and buy the stationery I need.'_

Somehow, that sounded extremely dull. If she was honest with herself, Mikoto was a bit annoyed that everyone was so busy while she was lazing around with nothing to do. Since last week, her close group of friends had been strangely hectic and elusive, always saying they had elsewhere to be whenever she called them. It just felt like… They were avoiding her on purpose…

Shaking her head, Mikoto jumped to her feet, a determined expression settling on her face.

"Alright, enough of this," she declared out aloud, a fist punching the air. "Even if I'm by myself, that's never stopped me before! I'll go find things to do on my own and have a smashing time–!"

"Talking to oneself is the first sign of insanity, Misaka says as she observes this alarming fact from Onee-sama."

Mikoto spun around on a heel, and blinked at the sight of her clone. Although they all looked the same, she somehow instinctively knew this was 10032, the first Sister to be saved from the cruel project that had involved mass-slaughter.

"Oh… It's you… Wait, what did you mean by that?!"

"From the records provided by Testament, Misaka knows that talking to oneself is the main sign of –"

"Alright, alright, I get it!" Mikoto interrupted. A blue spark sizzled from her forehead in irritation. "What are you doing here anyway?"

"Misaka is talking to Onee-sama and making sure she doesn't go insane, Misaka replies, fulfilling her role as the more responsible younger sister."

"…"

Mikoto glared at her mirror image, who simply gazed back with solemn eyes. Her Sisters were learning more about human emotions since the end of the experiments, but they all seemed to possess a natural talent in knowing how to push Mikoto's buttons. For 10032, her knack for sarcasm and jokes only seemed to grow worse (or better, depending on the perspective) as time went on.

 _'I guess I should be happy that they're developing in their own ways…'_

Mikoto sighed.

"Well, if you've got nowhere else to be, you can stay here; I don't care."

"Onee-sama should be more honest and say she is lonely, Misaka suggests."

"I am NOT lonely!"

"That is a lie, Misaka observes, but Misaka knows you too well by now and realises that this is a lost cause."

10032 stepped closer to Mikoto, the calm and collected expression never changing despite Mikoto's annoyed glare.

"Onee-sama should buy Misaka a drink for doing you this favour though, Misaka attempts to give her older sister a hint on the norms of etiquette."

A frustrated yell sent a flock of birds flying off in alarm.

"WHAT KIND OF A HINT IS THAT?!"

XXXXXXX

Mikoto lay her aching head on the cool plastic table, gloomily eyeing her Sister. Sitting opposite her with all the grace of a lady, 10032 was sipping away at a pineapple juice Mikoto had been forced to buy earlier from a nearby stall.

 _'Why me?'_ Mikoto lamented. _'I should have just left when I had the chance…'_

10032 elegantly put the cup down on the table.

"That had a very refreshing taste, Misaka states with satisfaction. The delicate citrus flavour that tingled the tongue wonderfully complimented the crisp coldness of the drink itself, Misaka comments. Misaka now feels obliged to thank Onee-sama, despite the fact that she had to coach her older sister about basic etiquette."

Mikoto slapped a hand onto her face with a grunt. "I'm not even going to bother…"

"Is something the matter, Misaka asks, now genuinely concerned about Onee-sama's well-being."

Pulling herself up slightly, Mikoto cupped a cheek and leaned against the table.

"No, not really," she sighed. "Today's just been a typical slow day, that's all."

"Onee-sama needs a better social life, Misaka observes."

"My social life is perfectly fine, thank you!" Mikoto snapped. She slouched languidly, and her shoulders drooped as she sighed for the umpteenth time.

"It's just… Well, my friends have been really busy lately... and I guess I just feel a bit out of the loop."

"Lazing about, partaking in delinquent activities while others do all the labour… Isn't that the very definition of a free-loader, Misaka asks matter-of-factly."

"Hey, that's not the point here!"

Mikoto absently gazed out towards the park before shaking her head.

"Never mind. Saten-san said she would join me later anyway. I just have to find something else to do until then."

"Misaka will stay with you, Misaka generously offers you her company."

"…That's meant to be a good thing?" Mikoto mumbled under her breath. "Besides," she continued more audibly, "you can't be here when Saten-san comes; she'll see you."

10032 stared at Mikoto for a long while in silence.

"What?" Mikoto asked. She suddenly felt like she was being scrutinised.

"Misaka finds it upsetting that Onee-sama tries so hard to hide her existence, Misaka admits frankly. You have never even once thought of introducing your younger Sisters to your friends, Misaka accuses Onee-sama with a depressed sigh."

A cold flame set alight in Mikoto's chest. She sat up, slamming a fist harshly on the table.

"No, that's not it! It's not like that at all…" Her jaws clenched and her eyes averted, settling on the white tabletop with a frown. Was that really how the Sisters felt? After all the promises she made, was she not being a good enough older sister after all?

"You guys were mixed up with that terrible project, backed by some of the most powerful people in this city. If my friends ever found out, they could be–!"

"Misaka completely understands, Misaka interrupts quickly in an attempt to calm Onee-sama down."

Mikoto looked up, confused eyes looking into those emotionless ones.

"Onee-sama is trying her hardest to protect the people precious to her by keeping us sheltered, Misaka shows off her grasp of the situation. You and the saviour helped us understand what that means, Misaka says with gratitude."

"Eh? But, but… You said…"

"It was something called a joke, Misaka confesses, lamenting the fact that Onee-sama is so dense."

"A joke is meant to be _funny_!"

"But it was funny, Misaka insists with a jovial laugh. Ha. Ha. Ha."

Mikoto facepalmed. "You really need to work on your sense of humour…"

Mikoto leaned back on her chair, and stared at the bright sky above without really seeing it. Although her Sister had insisted it had been a joke, a part of it had still stung deeply.

"Maybe…" the word quietly tumbled out of her mouth, and 10032 turned towards her. A comfortable silence lingered between them for a long moment, before Mikoto smiled at her Sister and continued. "Maybe someday, I'll introduce all of you to my friends properly. You girls are my family after all…"

As 10032 stared at her in wonder, Mikoto's determination grew.

"Yeah, I'll do that. So… can you all wait until then?"

Her Sister gently placed a hand on her chest, and nodded.

"We will wait until then, Misaka promises."

XXXXXXX

 _-Misaka-san, I'm out now! Where are you? I'll head your way asap!-_

On the edge of her phone screen, the numbers 11:35 blinked. Mikoto rapidly texted back.

 _-I'm at the park near Seventh Mist. See you soon!-_

Mikoto stretched out her arms and yawned loudly. She rubbed her eyes and returned to watching some kids play in the sandpits. Their laughter was shrill and full of excitement, making her already-soaring boredom level increase even further.

 _'Ahh… I just have to hold out a bit longer until Saten-san gets here…'_

Her Sister had left only a short while ago, announcing that she had personal errands to run. They had talked for a long time, 10032 relaying news from the other Sisters residing all over the world. It seemed they were making good progress and settling into the norms of human society, each starting to uncover their unique traits and talents. Mikoto was happy for them; it seemed the clones were finally discovering peace and joy in life that they so deserved.

Her mind drifted, skipping and churning over past memories and random stray thoughts. Not bothering to cover her mouth, she yawned loudly again.

"Misaka-san~!"

Mikoto jumped slightly. She turned her head to see a panting Ruiko running over. Suddenly feeling wide-awake, Mikoto cheerfully waved a greeting.

"Hey Saten-san, you found me pretty quickly."

Pulling to a stop, Ruiko rested her hands on her knees and took a moment to catch her breath. She slid next to the Level 5 on the wooden bench with a wide grin.

"I thought you already knew! I have a Misaka-san detector in my head!" She tapped a finger lightly against her temple. "It's my secret ability!"

Mikoto laughed. "That's kind of creepy, Saten-san."

"Hm…" Ruiko turned solemn, resting a hand on her chin in a thinking pose, "but mine is probably not as high level as Shirai-san's."

"Urrghh… That pervert."

Ruiko glanced at Mikoto curiously. "Did something happen?"

Mikoto rubbed the back of her head with a sigh. "She almost landed us into another detention this morning."

"Oh man, what did she do this time?"

"The usual," Mikoto said with a grimace, but it rapidly turned into a grin as Ruiko beamed back.

"Well, that's our Shirai-san for you!"

"Ahh~ I suppose. How did your catch-up work go by the way?"

"Wha-? Oh..! Uhh… I finished everything." For some strange reason, Ruiko averted her eyes as if she was uncomfortable, fingers fidgeting restlessly with the hem of her skirt. "It's probably not top quality, but sensei will have to learn to live with it. That topic was so boring!"

She made a funny face, but Mikoto had an odd inkling that something was off.

"What's wrong, Misaka-san?"

Noticing her friend glancing at her worriedly, Mikoto shook her head.

"Ah… It's nothing."

She was surely just imagining things. Why would Ruiko have any reason to lie about something as trivial as this?

"So… now that you're all done, want to head to lunch?" Mikoto asked.

"You bet! Let's grab Uiharu and Shirai-san from their Judgement office. I'm sure they're hungry too and need a breather from work."

"Hmph, I'm not going into that Judgement office ever again."

"Ehhh? Why not?!" Ruiko looked startled.

" ' _The office isn't a place for civilians like you to 'hang out' and chat, Onee-sama_ '," Mikoto imitated her junior's voice in a scathing manner. She scowled. "I'm not going!"

The alarm on Ruiko's face turned sheepish. "Eh… Shirai-san said that? Come on, Misaka-san, I'm sure she didn't mean it that way…"

"I'm not going!" the Level 5 said stubbornly. "Besides, Kuroko is hiding something from me. I'm going to get to the bottom of it, but I'm not going to let her win!"

Ruiko sweatdropped. "Uh... Haha… Misaka-san, this isn't a competition, you know… What makes you think Shirai-san is hiding something?"

"She's been all secretive and keeping me out of the loop lately!" Mikoto complained with a vivacious glower. "Civilian this, civilian that! It's _so annoying_! I just _know_ she's hiding something..!"

"Well, she wouldn't be the first…"

Mikoto froze, and the sour expression on her face melted into one of surprise and then regret.

"Ah, I'm sorry! I didn't mean it that way, Misaka-san!" Ruiko apologised quickly, suddenly realising how Mikoto had taken her words. "I just meant… People have their reasons right? I'm sure Shirai-san has her reasons too."

Mikoto stared at the ground. "You're right, Saten-san... Sorry… I know I also caused a lot of trouble for you guys…"

"Hey, Misaka-san," Ruiko chided gently, "wasn't that all in the past? You already apologised enough to us, and it's all fine! Just as long as you are aware we're always here to help you whenever you need it."

The corners of Mikoto's lips turned up into a small smile. Her spirited friend always seemed to know exactly what to say to make her feel better.

"Thanks Saten-san. I really appreciate it."

"No worries, Saten Ruiko is here!" With a victory sign, the long-haired girl suddenly jumped up from the bench, a big, mischievous grin blooming on her face. "Now Misaka-san, it's time for you to come with me!"

With that, she grabbed Mikoto's hand and began to pull her along.

"Whaaa-?!" Mikoto resisted in bewilderment, but her friend kept tugging harder.

"Come on, come on, just follow!" With a loud laugh, Ruiko broke into a run, dragging a very confused Mikoto by the hand. The electromaster had no choice but to trail after her.

"Wait, wait, where are we going, Saten-san?!"

"Let's elope together~"

"EHHHH?!" Mikoto's face immediately turned a beetroot red.

"Haha, you're so _adorable_ , Misaka-san~"

"Saten-saaaan!" Mikoto wailed. As they whizzed through the streets, some people looked on in curiosity as Ruiko pulled the red-faced Level 5 along.

"You'll find out our destination of love when we get there~!"

Hot steam almost poured out of Mikoto's ears in embarrassment.

XXXXXXX

"I told you, I'm not going iiinnnn!"

"Come onnnnn, Misaka-san!"

"Noooooo!"

Mikoto clung onto the staircase railings for dear life as Ruiko tried to wrestle the childish Level 5 away. It turned out Ruiko had brought them to the Judgement 177 Branch Office after all, where Kuroko and Uiharu worked. It was the very last place Mikoto wanted to go into, simply out of pride.

"It'll be okaaaay! Just commmeeee!"

"Noooooo, I'm not going! Just give it up alreadyyyy!"

Her arms tightly wound around Mikoto's waist, Ruiko was red-faced and sweaty all over from straining. The stubborn Level 5 electromaster was much stronger than she looked, and Ruiko was almost on the verge of giving up. But of course, she hadn't been Mikoto's close friend for nothing. A bright idea suddenly crossed her mind and she let go.

Mikoto exhaled in relief. She turned her head to glare threateningly at her friend.

"Just go in without mWAAAAAARGHHHH!"

Ruiko's fingers were suddenly at her neck and waist, ruthlessly tickling her sensitive skin. Mikoto chortled and gasped, her eyes tearing up at the weird sensations that were unbearably painful.

 _'Why the heck am I laughing?!'_

Mikoto struggled futilely against Ruiko's unforgiving fingers. Her weakening knees gave out underneath her as she continued to laugh and splutter.

"S-stop… Oh god… S…top…!"

Ruiko grinned. She paused her work and splayed her hands out in front of her like claws.

"I'll stop if you say you'll go in!"

"If you do that again…" A bright spark of electricity crackled from Mikoto's forehead as she shakily pulled herself up with the help of the railings. "I won't hold back!"

"Ehhh…" Ruiko's shoulders and arms sagged in mock disappointment. "You're no fun, Misaka-san. I couldn't help it; it's just so _cute_ when you get all sensitive like that~"

Mikoto's reddened cheeks puffed out, sulking at her friend's teasing.

"I'm not going in, no matter _what_ you say or do."

"Hai, hai~" Ruiko threw up her arms in a show of defeat. "I guess I'm no match for you."

Mikoto scowled as Ruiko grinned wickedly.

"Just bring Kuroko and Uiharu-san out already! I'll wait right here."

Ruiko laughed. "Alrighty~ I'm going, I'm going."

The long-haired girl rushed up the remaining stairs two at a time. Throwing Mikoto a mock salute, Ruiko turned the door handle and entered the office. The door shut behind her with a quiet click.

Mikoto flopped over the railing, and exhaled loudly.

 _'Jeez… That was exhausting. Saten-san can be so persistent…'_

She hung limply, letting her tired arms dangle down over the edge and resting a flushed cheek against the cold metal. An impatient rumbling resounded from her stomach, complaining that it was time for lunch.

 _'Ahh… It's only past noon and I'm so tired already…'_

She hadn't had proper breakfast either, so she was also famished.

 _'Wherever we decide to go later, I'm totally ordering a big meal.'_

She stayed in that position for a long time, listening to the bustling of streets outside and the permeating silence within the building. As time continued to pass, a slight frown pulled her eyebrows together.

 _'Shouldn't Saten-san be out by now?'_

Maybe Kuroko and Uiharu-san wanted to finish off what they had been doing before heading out for lunch. Maybe they were caught up in a long conversation. Maybe Konori-senpai was holding them back… Mikoto fought the growing urge to rip the door open and find out what was going on in there. She didn't want to lose against Kuroko in this stupid game of wills.

 _'Just how long does it take for them get ready for lunch?!'_

5 minutes… 10 minutes… 15 minutes…

The door still wasn't opening.

Mikoto stared daggers at the innocent barrier, and willed it to be unhinged by itself so she could take a peek inside. Leaning her back against the railing, she crossed her arms and tapped a foot impatiently. The curiosity was becoming overwhelming; she so badly wanted to know what was going on.

 _'No… I can't give in…'_

Had they already left without her? But no, that couldn't be possible. There was no other way out of that office… although, Kuroko could teleport. But why would they teleport out?

Unless…

Feeling an icy stab of sudden dread, Mikoto gritted her teeth and slowly climbed up the stairs. She paused before the door and then pressed one ear against the slight gap at the edges, straining to listen for a sound. At first, there was only silence, but then she began to hear faint whispers from inside.

'…you sure… is coming in..?'

'…yeah… just wait…'

'…oww… -san… my foot!'

'… sorry, sorry! …. Yikes!'

There was a brief scream before it got cut off. Mikoto's heart thudded wildly in her chest. Completely forgetting about her earlier pride, Mikoto quickly twisted the door handle and ran in at top speed.

"Saten-san! Uiharu-san! Kuroko! What's going -?! Eh?"

The room was completely dark and quiet.

Thin streams of light filtered through the slits of the drawn blinds covering the windows, but they did nothing to compensate for the lack of electrical lights. Mikoto blinked, her squinted eyes trying to adjust to the darkness. All kinds of possibilities rushed into her mind as her heart raced and grew cold. A blackout? A robbery? Terrorists holding her friends hostage?!

She tensed as she took a step forward, electricity ready to burst forth at any moment.

"SURPRISE!"

The ceiling lights abruptly turned on, accompanied by loud bursts of mini-explosions that sounded like gunfire. A multitude of colours erupted into her vision from all directions. In a whir of panic, Mikoto stepped backwards and slipped, her electricity already roaring out in her defence before she even hit the floor.

She heard screams as the lights flickered out, plunging the room into darkness again. Mikoto groaned as she pushed herself off the ground in a daze. There were big blotches in her visual field where the flashing lights had been.

 _'What was that -?'_

"Ow, ow, ow… That rather hurt..!"

An unexpected voice sounded from the darkness and Mikoto's eyes widened in recognition.

 _'K-Kongou-san?! What's she doing here…?!'_

"Could someone please pull the blinds back up?"

 _'Eh? Wasn't that..?'_

"Or turn the lights back on."

"Where is the switch again?"

"It should be around here – "

"Ow! Uiharu! That was my nose, dammit!"

"Oh oops, sorry Saten-san!"

"… Onee-sama must have short-circuited the lights…"

"Ara~ I never knew my Mikoto-chan gets scared so easily~"

Mikoto stilled at the new voice. It couldn't be… Was she hallucinating?!

Light suddenly flooded the room as the blinds lifted from the windows, the bright afternoon sunlight making everyone cringe. Mikoto squinted, forcing her eyes open to take in her surroundings. As she looked, her mouth dropped open in shock.

 _Everyone_ was there.

As was expected, Kuroko, Ruiko, and Kazari were there along with Konori Mii… But then there was Kongou Mitsuko, standing together with her close friends Awatsuki Maaya and Wannai Kinuho… And leaning against a chair next to them was…

"Mama?!"

Mikoto blinked, wondering if she was really dreaming.

Misaka Misuzu simply grinned and waved like nothing was out of the ordinary.

"Hi~ The one and only, Mikoto-chan~"

"But… But… How… Why…?"

Her gaze travelled around the room again, and finally noticed the obvious details she had missed. The office was decorated flamboyantly, complete with streamers and colourful helium balloons. Huge letters hung from the ceiling, their carefully glittered surfaces shimmering merrily.

Mikoto trailed her eyes over them, and her mouth gaped further open.

"Happy… Birthday… Misaka… Mikoto?" She read out in disbelief.

"HAPPY BIRTHDAY!"

As everyone in the room shouted out in unison, Mikoto looked around at all the smiling faces of her dearest friends, blinking in awe and sheer surprise. She didn't know what to think, what to make of this… but a countless number of emotions that she could not name swirled up to the surface.

"You guys…" she whispered. "This is all for me…?"

Arms suddenly flung around her shoulder, the familiar scent of her mother further adding to the whirl of confusing feelings.

"Mikoto-chan~ Don't tell me you forgot your own birthday again?"

"Well…" Mikoto averted her eyes with a guilty smile, "I guess I just wasn't thinking of it…"

It _was_ May 2nd after all… but it had been _years_ since she had last properly celebrated her birthday. Of course, her parents always called and often sent her gifts by mail, but Mikoto had never cared to advertise her birthdate publicly, even amongst friends. As she grew to become more of a celebrity figure in Academy City, the date had faded to insignificance, and eventually ended up being just like any other of the year. It usually slipped past Mikoto's notice until she received a reminding phone call from her parents.

"That's no good, Mikoto-chan!" Her mother hugged Mikoto tightly in front of her friends, making the electromaster blush. "You need to be more self-aware!"

"She looks plenty self-aware to me right now~" Mikoto heard Ruiko whisper as Kazari giggled, and she shot them both a half-hearted glare.

"Mama!" Mikoto protested. "You're holding me too tightly!"

"Aww, but I haven't seen you in so long! Surely, you missed me too?"

"Hai hai, I missed you Mama, but I need to breathe!"

Misuzu laughed and finally let her go.

"It's a good thing you have such wonderful friends, Mikoto-chan. They organised everything and even invited me along! Your Papa couldn't make it though… He said to pass on the Happy Birthday wishes!"

Mikoto smiled, her eyes softening. "Thanks Mama… Papa…"

She looked over to her friends, and her fluttering heart further warmed at their happy smiles. It was simply wonderful to know people cared so much to prepare an amazing surprise like this. So much effort had taken place here, Mikoto could tell. In every decoration, she could see her friends' personal touch and intense dedication, and all the time they had sacrificed, just to make this happen.

"This is… I… I just…" She stumbled and struggled to express herself, then stopped and took a deep breath.

"Thank you so much!" Mikoto blurted out. She wished she could convey her gratitude properly, and somehow show just how much she treasured her friends in return. She did not think measly words were enough, but her friends seemed to understand.

They always did.

"Misaka-san! It's your special day, so you have to enjoy yourself!"

"That's right!" A green fan spread out elegantly. "Kongou Mitsuko will not allow this party to be anything other than perfect!"

"Just try not to blow up the place with your ego," Kuroko muttered under her breath.

"I'm starving! Can we eat now?!"

"Yes, there is plenty of food for everyone~!"

"Oh my, what lovely treats! Have a look at this one, Awatsuki-san!"

"That looks delicious, Wannai-san! I wonder who brought these - "

"I think Saten-san baked them."

"You brought those tasty-looking white cookies, is that right, Wannai-san?"

"I'm not much of a cook, so I hope they're okay…"

Mikoto simply stood, staring at the huge piles of food in wonderment. Kuroko was suddenly next to her, and gazed up at her questioningly.

"Come on Onee-sama, these are for you… Ah, unless you want Kuroko to feed you-?"

That snapped Mikoto out of her stupor.

"I can eat for myself!"

Still, she paused and turned to her junior.

"This is amazing… I… S-sorry, I actually thought you…"

"You thought I was hiding something important from you, right?" Kuroko smiled, taking Mikoto's guilty silence as a confirmation of her suspicions. "In that case, I should be the one apologising for all the secretiveness I and the others showed for the past week. I'm very sorry, Onee-sama."

"Ah man~" Ruiko came up beside them. "It was tough having to lie like that this morning, Misaka-san! I kept wanting to blurt out the truth!"

Kazari shook her head at Ruiko, and held out a plate of cupcakes for Mikoto to take. "Jeez Saten-san, it would have been pointless if you'd spoilt the surprise!"

"I know, I know~" Ruiko grinned as she grabbed a cookie. "I only considered it a few times."

Kazari sighed in mock despair, amusement in her eyes. "Oh Saten-san… At least it didn't actually happen. We managed to make it a surprise after all."

"Yeah, I was _very_ surprised!" Mikoto took a bite out of the chocolate cupcake and swallowed hungrily. "And this is so tasty! I had no idea you guys were planning something like this…"

"Well, it was Shirai-san's idea from the very beginning. She came up with the whole thing and did most of the work."

Mikoto turned to Kuroko. "You did…?"

Kuroko tossed back a pigtail, averting her eyes modestly with a slight blush. "Ah well, anything for you, Onee-sama."

'Ah… That was the reason why you didn't want me coming into the office, right?"

Mikoto suddenly felt a bit silly. Her cheeks reddened as she recalled how stubborn she had become over the whole issue.

Kuroko nodded while Ruiko huffed. "When you refused to come in though, I was in pickles!"

"Sorry, Saten-san," Mikoto apologised with a good-natured laugh. "You guys were too good at this; I really had no idea!"

Her three friends grinned in victory, and rushed to swamp Mikoto into a group hug. Mikoto's face flared crimson even as she smiled and hugged in return.

"Mikoto-chan~ You didn't let me hug you properly before! I want in too~"

And then her Mama was there, along with Konori-senpai, Kongou-san, Awatsuki-san and Wannai-san. Smiling and laughing together.

Mikoto knew, right then and there, that these special people in her life were her greatest happiness.

There could not be better proof than this moment.

XXXXXXX

The party was an absolute blast.

Mikoto had the best time she'd had in a long while. They celebrated non-stop for hours in a carefree manner. They talked and ate, shared laughter and good memories, capturing them all with a camera to reminisce later. Her friends sang Happy Birthday for Mikoto, and brought out a huge Gekota cake along with a present Mikoto knew she would treasure forever. Her friends had all contributed to getting a new violin case for her – constructed by a respectable brand and polished with the finest finishes. When she had opened the case however, it was what she found inside that had touched her the most. The empty felt spaces were elegantly decorated with photos of some of the good times they had spent together in the past, a storage of precious memories. The case also contained a violin cover that had her favourite animal characters etched onto it, making Mikoto tear up with happiness because they were so cute.

"Shirai-san designed that," Ruiko and Kazari had told her. Mikoto had smiled; despite Kuroko's constant nagging about her childish tastes, her junior was always supporting her in her own ways too.

Kongou Mitsuko and her group had left earlier after helping them clean up. Mikoto's mother also had to leave in order to catch the last bus out of Academy City. The four girls were now sitting in the office along with Konori-senpai, a shared satisfied expression on all of their faces.

"Ahh… I'm so full now, I can't move at all." Ruiko complained loudly.

Kazari peered at her with a raised eyebrow. "Honestly Saten-san, didn't I tell you not to overdo it with the cake?"

"But, but it was sooo goood… Besides," The long-haired girl gave Kazari a sly look, "how many slices of cake did _you_ have, Uiharu?"

Kazari's cheeks flushed. "S- Saten-san! That's not fair!"

"Was it equivalent to the number of polka dots on your panties today~?"

"Ehhhh?! Wh- When did you look…?!"

Mikoto sighed contentedly as Ruiko and Kazari continued to squabble. She glanced over at Kuroko who was sipping a cup of tea and quietly talking to Konori-senpai about some Judgement work to be finished.

She closed her eyes, and leaned back on the couch with a smile. What a day it had been, something so seemingly ordinary brightened up by a certain special surprise. She realised again just how lucky she was, to have such amazing and talented friends who were also very dedicated.

 _"Misaka-san, a birthday only happens ONCE a year, so it's a date that can't be missed, no matter what!"_

Mikoto's smile grew bigger, recalling Ruiko's fiercely-spoken words. She supposed she would have more reasons to remember her birthday from now on, especially after creating such good memories today…

Suddenly, she sat up.

"Hang on."

As if she had spoken into a microphone, an abrupt hush fell in the room and four pairs of eyes turned curiously towards her.

"How did you even find out about my birthday?" Mikoto continued wonderingly. "I don't think I ever told anyone here…"

She gazed around at each of them in turn, then finally zoned in on Kuroko who suddenly looked uncomfortable.

"Shirai-san said she found the date in your old picture album," Kazari piped up happily. Behind her, Kuroko stiffened. Sweat began pouring out of her forehead like a monsoon. "She said the date was written on a picture of you at a family birthday party when you were very little."

Kuroko was visibly shaking. The teleporter slowly turned her face away, pretending to be occupied with something else…

"Kuroko."

The pig-tailed girl twitched. With a great amount of effort, she twisted her neck back to face Mikoto with a frozen smile.

"Y-yes, O-Onee-sama?"

"Do you know where I keep my old photo albums in our room?"

"N-no… Of course, I wouldn't know that…"

"They are _locked._ In a _box_. Under my bed."

"Ah… They are?"

"I wonder how anyone could have gotten hold of something that had been _locked_ away like that?"

"H-how indeed…?"

"Maybe someone, like a certain perverted teleporter?"

"…"

"Kuroko."

"Y-yes?"

"You better be ready for punishment."

Outside the Judgement building, everyone passing by stopped in astonishment as blue lightning flashed from the second floor windows, accompanied by loud screams of pain and pleasure.

XXXXXXX

As she was heading back home, Mikoto suddenly realised something.

The Sisters… They didn't have birthdays, did they?

Although they had been created into this world, they probably had no idea of the exact dates. Did they even know what a birthday was?

 _"Misaka-san, a birthday only happens ONCE a year, so it's a date that can't be missed, no matter what!"_

A date that couldn't be missed… A special day to celebrate the existence of a person…

 _'They deserve to be celebrated too…'_

"Onee-sama? Is something the matter?"

Mikoto jerked out of her reverie, and turned to face Kuroko who was peering up at her questioningly.

"Ah, it's nothing. I was just thinking…"

They continued on in comfortable silence, heading towards their dormitory and enjoying the last of the afternoon's fading sun.

"Hey Kuroko," Mikoto spoke up earnestly. "Thank you for today. I had a really great time with everyone, and I appreciate all the hard effort you put in."

Her junior smiled at Mikoto's rare show of honesty. A slight blush reddened her cheeks to match her auburn hair.

"It wasn't only me, Onee-sama. We all wanted to do this for you," Kuroko said. "From now on, there will be no more of forgetting birthdays."

Mikoto chuckled. "I'll leave it to you then, Kuroko."

Kuroko's blush deepened, her eyes widening at her Onee-sama's trusting words. She flung herself around Mikoto's neck, and clung onto her with a happy smile.

"Kuroko will do her very best, Onee-sama!"

"H-hey! Don't cling so suddenly!"

But despite her words and struggles, Mikoto was glad Kuroko was with her.

XXXXXXX

 ** _Sunday, 3rd May, afternoon_**

"You were looking for me, Onee-sama? Misaka asks, wondering what favours her older sister might be wanting this time."

After hours of searching around Academy City, Mikoto had finally found 10032, the person she had been looking for. Now that she was right in front of her though, the electromaster realised she had no idea what to say or how to go about explaining the situation.

"I… It's not that…" Mikoto gulped. Her heart was thumping wildly in her chest, the cold anticipation fiercely twisting her stomach that was filled with jittering butterflies.

"What is the matter, Misaka enquires, pondering if Onee-sama is sick with a fever since she is so red."

10032 tilted her head, gazing at Mikoto with her usual, solemn eyes. For some reason, it only unnerved the Level 5 further.

"W-well…" Mikoto's eyes fixated on the ground. Her hands fidgeted restlessly with something hidden behind her back.

"Y-you can relay anything you see or hear across the network, right?"

"Misaka can indeed, Misaka affirms."

"Th-then, c-can you do something for me?"

"So Onee-sama is here to ask a favour of her more responsible younger sister after all, Misaka confirms her suspicions with a sigh of resignation."

"This is important!" Mikoto defended her request fiercely. "I… You'll see what I mean!"

From behind her back, Mikoto whipped out a small wrapped box, decorated carefully with a fancy blue ribbon. She thrust it at 10032 with both hands, her eyes burning with intense determination.

"Open this and relay all of the contents across the network! Make sure every one of you sees and hears, okay?!"

10032 stared at the package blankly.

"Is this a gift for Misaka, Misaka asks in surprise at Onee-sama's sudden display of charity."

"J-just take it!"

Hesitantly, 10032 took the box from Mikoto. Then, with only a slight moment's pause, she began to undo the ribbon with great focus.

"Wait, wait!" Mikoto cried out in alarm. "Open it after I leave!"

"Why, Misaka asks, pausing only because she would like to hear Onee-sama's reasoning behind her troublesome request to wait."

Mikoto's face and neck felt like they were on fire.

"It's… I- I'm leaving now! Bye!"

Before 10032 could utter another word, Misaka Mikoto turned around and became a blur that faded into the crowded streets ahead.

XXXXXXX

All over the world, the Sisters received 10032's latest news. Onee-sama had left her a package, which she had mysteriously asked to be relayed across the network. 10032 was requesting every Sister to tune in and pay attention as she opened it.

"What is it, Misaka 18733 asks in confusion."

"Misaka 17632 is curious as well, Misaka confesses."

"Misaka 10032 is unsure, but Onee-sama was very adamant about this. She also ran off at top speed after giving Misaka this package, Misaka notes."

"Misaka 13234 thinks Misaka 10032 should open it quickly."

"Please do hurry up, Misaka 13878 agrees with Misaka 13234."

"Misaka 10032 is opening it now, Misaka asks for patience."

The network grew silent as they saw the gift being unwrapped in their minds. Each Sister observed in real-time, sensing, seeing and feeling everything 10032 was. Inside the box was a colourful card decorated with flying birds, which 10032 promptly opened to read.

 _"To my dear little sisters,_

 _My friends reminded me yesterday that a birthday only happens once a year, to celebrate a special person's existence. Maybe you don't know the exact dates of your births, but I think it's important…_

 _So would you allow me to share my birthdate, May 2nd, with you all?_

 _I know this is a day late, but here's to your very first celebration:_

 _Happy Birthday!_

 _Continue to live, and enjoy every day with smiles._

 _-From your Onee-sama-_ "

There was another object in the box, something that looked like a recording device. 10032 took it out carefully and pressed the round button on its surface.

A beautiful sound of a violin flowed out, playing the melody that the Sisters immediately recognised as the "Happy Birthday" tune from their knowledge of Testament. There were unique embellishments that deviated this recording from its original version, personal touches that the Sisters identified as their Onee-sama's individual flair and creativity. Their connected minds acknowledged this display of great talent, but at the same time, they also appreciated how the soaring sound reverberated in the air with so much care, joy and love.

This was their Onee-sama who had protected them, who had been willing to sacrifice so much for their sakes and gave them a second chance at life.

This was their Onee-sama at her best, who was willing to share her special day with them all.

Across the network, new and nameless emotions spread, resounding with the bright warmth in all of the Sisters' hearts.

* * *

 **A/N:** Thank you for reading! This piece was devised from a sudden idea, and it wouldn't leave me alone so I just had to write it. It's a little different to my usual style, but it was a great learning exercise and change of pace. I really enjoyed the challenge of trying to capture the essence of Railgun in a short piece, and I hope I've succeeded somewhat. Hopefully you enjoyed reading it too. Reviews and constructive feedback are greatly appreciated! I would love to know your thoughts on the work. Thanks!


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